I have "NoScript" running (I think!) but as to what choices to toggle in
the program menu - they are ALL JARGON which I do not understand !
I don't even know if it actually IS doing anything...

My experience with NoScript is that it blacklists everything by default,
and that you generally have to whitelist (temporarily or permanently),
individual scripting hosts.
At first level of user interface, the default handling is to put a small
icon in the toolbar at the very bottom of a Seamonkey window. In my
display, that's between the lock icon that shows certificate
information, and the icon shown by AdBlock Plus. In my own
implementation, I also tweak my Navigation toolbar at the top of the
display. If I right-click on that toolbar, and select "customize", that
allows me to drag NoScript buttons into the toolbar. The buttons for
Temporarily All Scripts in this Page, and Revoke Temporary Permissions
should be self-explanatory. If you use the NoScript button, that's the
same thing as you get with the icon at the bottom of the page.
If you dig further into the options settings, there's stuff that's a lot
more cryptic, and I don't understand a lot of them myself, especially in
the Advanced tab -- a lot of that assumes knowledge of web page design.
For most of what you want, the settings would be in the General and
Whitelist tabs. For most of the stuff in the other tabs, default
settings should be adequate, unless you know you have specific reason to
change something.
NoScript has a lot of power, but it takes some tinkering with to get it
tuned for what you want, especially in handling whitelisting or marking
specific scripting hosts as permanently untrusted.
For me, I'm generally content to leave nearly everything blacklisted, as
a default, and then temporarily whitelisting, when needed. But even that
takes a bit of tinkering. There's certainly sites that I trust (e.g,
scripting coming from the domain name itself), and I trust certain
scripting engines. Scripting from content mirrors (such as cloudfront),
or Content Delivery Networks (with CDN) are generally candidates for
whitelisting. On the other hand, stuff from advertising networks (many,
but not all may have "ad" in the name, such as adsonar) are worth blocking.
Depending on your browsing habits, some scripting hosts deliver both
stuff you want to see and stuff you want to block, and sometimes you
have to choose to accept the garbage, for stuff that you want. This is
especially true with some sites that use the same scripting host to
deliver auto-play media content, photos, and text content. I've also
found that with some sites, it takes multiple runs of "Temporarily allow
all on this page". Some scripting hosts may not try to deliver stuff
immediately, until you've granted permission to other scripts. And this
is especially true with sites that do forms (particularly purchasing).
Occasionally, I'll get part way into a form, and discover that there's
scripts that are blocked. When I enable the scripts (and the browser
repaints the page), then I get a clean form, having lost everything
that's already been entered.
If you're simply trying to block scripts when they get to be intrusive
or obnoxious, another approach could be with PrefBar. One of the
options there is JavaScript, and if you have that enabled, it's a mtter
of just toggling a tick box on a toolbar, to turn on or turn off
scripting. I don't use that one, but I make occasional use of similar
options of blocking/enabling images, cookies, sending referrer data, etc.
Smith

There are actually two PrefBar options for stopping JavaScript. Both
are in the vanilla PrefBar.
* "Javascript (Tab)" works on the current tab or window. For this one,
you have to move it from Available Items to Enabled Items.
* "JavaScript" works on any subsequently launched tab or window but not
on the current one. This one should already be in Enabled Items.
When I set these up, I called the first one "Local JavaScript" and the
second one "Global JavaScript".
NOTE WELL: All this becomes defunct when SeaMonkey transitions to
Webextensions. :(

WHAT does that mean !? "All this becomes defunct when SeaMonkey
transitions to